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发表于 23-4-2010 11:06:44
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Scania XPI injection system
After five years’ development at the Scania Technical Centre in Sweden, Scania says its new Euro V engine platform is ready for the market, starting with five- and six-cylinder inline engines. It will gradually replace the current platform over the next few years. Euro V becomes mandatory within the European Union in October 2009.
Exhaust gas recirculation (EGR) via the Scania XPI injection system, developed jointly with Cummins, was designed into the system to meet performance, emissions, and fuel economy targets. The EGR system allows emissions to be lowered during combustion via high injection pressures, eliminating the need for aftertreatment equipment and tanks to carry additives onboard the vehicle. Scania has cooperated with Cummins to develop injection and combustion technology since the early 1990s. Scania HPI, launched in 2001, was the first result of the alliance.
Scania has developed a new-generation engine management system to control functions such as fuel injection, dual-stage EGR, charge-air, cooling fan and engine operating temperature, variable-geometry turbocharger (VGT), exhaust braking, NOx control, exhaust aftertreatment, and engine oil level. The control unit is mounted on the cool side of the engine. On six-cylinder engines, the unit is cooled by the flow of fuel from the tank to the low-pressure pump; five-cylinder engines do not require more cooling than that provided by the airflow when driving.
Development of the common-rail fuel injection system, Scania XPI (extra high-pressure injection), allows a high degree of freedom in terms of injection timing and pressure. With common-rail, injection timing and duration are independent of the camshaft. High injection pressures are available at any time, irrespective of engine speed. It also opens the possibility to use several injection pulses.
这是斯堪尼亚的XPI系统,还有译文:
斯堪尼亚XPI(超高压燃油喷射extra-high pressure injection)燃油喷射系统
瑞典的斯堪尼亚技术中心在历经了5年的研究与开发后宣布,其最新研发的欧Ⅴ排放标准的发动机平台已准备投向市场,开始应用在直列5缸和6缸的发动机上。在未来数年里它将逐步取代的现有发动机平台。自2009年10月起欧盟颁布的欧V排放标准将强制生效。
该中心与康明斯所联合研发的基于斯堪尼亚XPI燃油喷射系统的废气再循环装置,经设计已被应用于发动机系统,使得发动机性能、排放控制以及燃油经济性方面均能达到预定目标。废气再循环系统通过高压燃油喷射降低了燃烧过程所生成的排放物,从而无需排气后处理装置,也不用在车辆上安装其他附加装置。斯堪尼亚技术中心与康明斯自20世纪90年代初开始合作研发发动机燃油喷射和缸内燃烧技术,于2001年所研发出的斯堪尼亚 HPI,便是两家合作的第一项成果。
斯堪尼亚技术中心已开发出新一代的发动机管理系统,以控制发动机的一些功能,诸如燃油喷射、分级废气再循环、空气压缩、冷却风扇、发动机运行温度,可变截面涡轮增压器(VGT),排气制动,氮氧化物排放控制,排气后处理和发动机机油油面高度。控制单元被安装在发动机较冷的一侧。在6缸发动机里,控制单元由从油箱流向低压油泵的燃油来冷却;而5缸发动机仅由在运行过程中空气流动冷却就可以,无需其他的冷却方式。
随着共轨燃油喷射系统的开发,斯堪尼亚XPI(超高压燃油喷射)使燃油喷射系统喷油正时及喷射压力方面有了更大的自由。由于共轨系统的应用,喷油正时和喷油持续角相对于凸轮轴独立的。高压喷射可以不考虑发动机速度,并可在任何时刻应用,也让使用几个喷油脉冲成为可能。 |
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